How do I remove green background without replacing it with another background?
For this Explanation i will use a clip of an alpaca on a greenscreen from here -
https://www.videvo.net/video/alpaca-on-green-screen/3442/
Step one - setup
Open blender with the General preset

And select the Compositing workspace

Select use nodes

Step two - add nodes
Remove The render Layers node by clicking it and pressing X on the keyboard

Add a Movie Clip node by clicking the add menu

Select the sub-menu Matte

And select Keying and drag the node to left of the Composite node

Add Movie Clip Node with Add -&gt; Input -&gt; Movie clip


Click Open On the Movie Clip node and select the video clip
Add a Viewer node with Add -&gt; Output -&gt; Viewer

and place it under composite node

click the yellow circle on the movie clip node and drag the mouse to the Image input on the left of the Keying node and connect all the other nodes as in the image

you will notice the clip in the background
Click V on your keyboard a few times to zoom out or Alt+V to zoom in so that you can clearly see your video.
Step three - Keying node
Select a frame in which there is a subject on the greenscreen
By changing the frame

Click The Color Input on the keying node

Click The eyedropper icon

And Click The Green on your image if there are darker and lighter areas click somewhere in the middle

you will see the green vanish but it won't be perfect every time so we will tweak some settings
Set The Feather Distance to about 2 or 3 pixels

Then Change the Dilate/Erode to some negative number that doesn't cut away from the character

Play with settings until it looks right
Step four - render
First set the End to the last frame of your shot which you can find by changing the frame

on the right select the output properties

Make sure the file format is set to png
and RGBA

Press the select file button

select a output folder and make sure it is empty because it will fill with images
and press accept on the bottom right
Now all you have to do is render out the animation
select it from the render dropdown and wait for it to finish.

when the image Stops changing Your Done!
You can import a image sequence in most video editing software including blender and the background is removed
Step 4 - finish
close blender with the big red X on the top right when it finishes rendering